The use of focused optical radiation to treat certain problems of the eye began in the early 1950s. The advent of the laser in 1960 made it possible to consider laser optical sources instead of incoherent sources. Lasers offered the advantages of much higher power, narrow wavelength band, smaller focused spot sizes, and better absorption in the target tissues.
Although ophthalmology was the first discipline to use optical radiation to treat disorders, the availability of laser radiation of higher power made it possible to extend the application of lasers to many other medical specialties.
Among the many lasers that have been developed, the carbon dioxide laser, with an emission wavelength of 10.6 microns, offers very useful medical applications because it is absorbed to a very great extent by almost all tissues of the body. Thus, by focusing this laser on tissue, it is possible to photocoagulate, to cut, or to vaporize almost any tissue in the body. Accordingly, the carbon dioxide laser has found application in a number of disciplines such as otolaryngology, neurosurgery, gynecology, and in general surgery, where the laser is used to make incisions with minimum damage to surrounding tissues, to coagulate small arteries and veins, thereby minimizing blood loss, and to vaporize various tumors and abnormal tissues.
A number of instruments have been proposed and a few have been developed for use in a number of applications. These devices typically comprise a laser and an articulated arm with a series of mirrors to direct the beam to the target area. The systems that have been proposed or developed have a number of disadvantages that make their clinical application difficult. Some systems are awkward to use clinically because the laser is directly attached to an operating microscope. In others, the articulated arm contains a large number of mirrors (up to eight mirrors) and has long arms so that the systems require constant attention, extreme care, and repeated realignment in the clinical setting.